Havoc
by some metalhead
Summary: AU. When Okumura Rin goes missing during a mission for the vatican, his children are left behind with no one to teach them how to avoid the ill fate that awaits them.


**I**

...

息**  
**

The entire room was a pandemonium of crying kids and broken toys, and even the young teacher was in the verge of crying as she hid from the demon child who had caused such a chaotic the middle of the room there were two little boys. One of them was hurt— his nose was bleeding, and he held his broken arm tightly as he cried his eyes out for his mother to come and save him. The other one, on the other hand, was completely blinded by rage and hate, staring at his bleeding fists as he panted exhaustedly.

To Rin, this situation felt like an enormous déjà vu— probably because he saw a mirroring reflection of younger self in his son.

"What are you lookin' at?!" the angry little boy barked at the other children, who were taking shelter from him behind tables and chairs. "Stop lookin' at me! Leave me alone, _dammit_!" And then, he began throwing whatever he could get his hands on— toys, books, plantpots and even chairs and tables.

"Yoru!" As soon as he heard that familiar voice, he immediately stood still and became quiet, almost as though he had frozen. Reluctantly, he turned to face his father, whose expression was one of nothing but indignation. "Come here, we're going home."

"But—"

"_Now._"

Everyone stared in disbelief as the usually defiant boy did as he was told; he quickly let go of the toy (which he was planning to throw at his teacher) and rushed towards his father, who immediately grabbed him by the hand and dragged him outside the room. The kindergarten was now silent again, but the fear and the blood stains were still there.

...

"B–but I didn't do anything bad!" Yoru sobbed, tears streaming down his cheeks. "I... Th–they started it! They—"

"You _did _do something bad!" Rin cut him off firmly. "You do _not_ hit other children, Yoru! How many times do I have to tell you that?"

"But _dad_! I... I _tried_ to be nice!" Yoru wailed, fists clenched in both anger and grief. "I really tried... but...! They kept callin' me demon and... And that really pissed me off, so I punched them!"

Rin knew exactly what his son was going through and how tough it was to deal with rejection as he had experienced it first hand when he was a kid. He felt bad for scolding the boy (especially when he related with him and his internal struggles) but he knew he had to do, because he didn't want him to feel as rejected as he had when he was a kid. Besides, Rin couldn't really blame the kid for his volatile personality— especially knowing he was the one from whom the kid had inherited his bad temper.

"You can't just go around punching people that piss you off, Yoru. Believe me, you'll regret it, and one day you'll find yourself all alone," Rin said, and a wave of nostalgia swept over him as he was giving his son the same advice his father had given him years ago. "Just... try to control your temper, okay? If you do, I'm sure you'll have tons of friends in no time."

"I don't _need_ friends," Yoru scoffed, looking anywhere but at his father's face.

"Everybody needs friends, Yoru." Rin said, and tried to give his son a pat on the head but the latter deftly avoided his hand.

"No, I don't!" Yoru snapped. "I don't need anyone! I... I just..." he trailed off, his angry expression suddenly growing gloomy. "I just need mom..."

"... That's why I'm going to look for her," Rin said, and the little boy's face immediately lightened up. "But," he kneeled in front of his son and grabbed him by his shoulders. "You have to promise me you'll be a good boy; that you won't hurt other kids, and that you'll take care of your siblings while I'm gone, okay?" Yoru remained silent, his icy blue gaze downcast. "You promise?"

Yoru sniffed, looking up at his father with teary, red eyes. "I promise..."

族

"Remember, feed the twins every three to four hours. Try to feed them one straight after the other, even if only one of them is hungry. You might not believe it but it's _real_ important you keep the schedule— trust me, you'll sleep a lot more at night if you do," Rin told, or rather, instructed his younger brother. "Yoru is a bad tempered kid— don't let him do whatever he wants. If he and his sister fight give them a time out in different rooms until they calm down and apologize to each other, alright? Also, make sure Chiasa actually finishes her meals. If she gets faddy and refuses to eat, take away her snacks and sweets. Got it?"

Yukio blinked, turquoise eyes wide in astonishment at his older brother's hidden sense of responsibility. Between them, Rin had always been considered the immature one— always getting into fights, skipping school and failing classes. So to his twin brother, who had known him ever since they were born, it was appalling to see how attentive and reliable he had become over the years.

"If only you had been this mature a few years ago..." Yukio commented under his breath, earning himself an irritated glare.

"Shut up, stupid four eyes..." Rin murmured, proving that no matter how much time passes, there were some things that would never change— such as his hot temper, and his ambitious desire to become the best exorcist in the entire world. His angry expression then softened into a weak smile, feeling grateful that his brother was there to help him— but at the same time, guilty as he knew he was throwing a heavy weight on his shoulders.

Yukio immediately noticed his brother's expression, and almost as though he had read his mind, he told him, "Don't worry, Nii-san... Everything will be okay."

Rin's smile widened. "Surely it will," he said before turning around and waving his hand at his younger twin. "See you soon, Yukio..."

...

It had been only a few days since the four kids had moved with him, and honestly, Yukio was expecting much worse. For children who were (_literally_) demons, they were behaving surprisingly well. The baby twins were rather quiet, and didn't cry as much as he thought they would; the other two siblings, on the other hand, were natural rioters— but certainly not as vicious as he had expected them to be.

"You two are ready?" Yukio asked, and the two children (who were wearing their colorful, kindergarten uniforms) nodded with enthusiasm. With a smile across his lips, he watched the two siblings as they rushed towards their nursery school, and a feeling of nostalgia suddenly filled him— perhaps because they reminded him of himself and his older brother when they were kids. This pleasant feeling didn't last much, though— and his expression grew desperate when he noticed something rather alarming. "Wai— YORU!" he yelled, and the little boy turned around, confused.

Yukio knew he couldn't possibly say it out of loud, so he simply gestured the little boy to look behind his back— where his black tail was waving in excitement. Realizing his tail was at the sight of everyone, Yoru quickly did what his father had taught him: entwine it around his belly, and hide it under his clothes. "Sorry, Yukio-ojisan!" he shouted, a cheerful grin across his face. "Won't happen again! Promise!"

Yukio hoped that was true; otherwise, there could be _serious_ problems. Then again, he wasn't that concerned— after all, only people with spirit wounds would be able to see the children's demonic traits (such as their tails, pointed ears, sharp fangs, and the bright red gleam that usually appeared on their pupils whenever they were angry), and he doubted anyone in the kindergarten had one. However, that didn't mean taking risks was an option; they had to be _extremely_ careful, especially considering the children's demon hearts weren't sealed.

Wondering why Rin had taken such a risky decision— the decision of leaving his children's demonic heritage unsealed— Yukio couldn't help but feel concerned about their future.

It was true that the vatican had allowed his brother to live despite being a major threat to humanity, but honestly, he doubted the same would apply for his children if they happened to show any sign of having inherited the so deadly blue flames. Much to his relief though, it seemed like the demonic power had skipped this generation— but then again, they couldn't be at ease.

Pinching the bridge of his nose, he let out an exhausted sigh as he tried to empty his mind from such negative thoughts.

優

"Turmeric is very good for healing wounds with suppuration, but you could also use sanch—" Shiemi suddenly cut herself off, her face heating up as she realized the mistake she almost made. She could never get rid of the quirk of naming plants and herbs with peculiar names, so whenever the words _sancho-san_ or _homairi_ accidentally slipped from her lips in front of the customers, she looked down as a pinkish blush spread on her cheeks. "Y–you could also use aloe... It has astringent qualities, and works very well for injuries like burns."

After what seemed like an eternity, the customer finally gave his answer, "Well... I'll take a bottle of aloe vera extract, please."

Wearing a warm smile across her face, Shiemi handed him the product. "That'll be ¥750, please." As soon as the customer paid the money and left the exorcist shop (obviously after she dismissed him with a sweet "thank you, come back soon!"), a relieved sigh escaped her mouth as she felt she finally could relax again.

Shiemi was exhausted— it had been quite a busy day at the shop; not only because of the many customers, but also because she had been babysitting two baby twins almost the whole day. Curious as to why they were so quiet, she looked down at the basket bassinet next to her and saw that both babies were fine— sleeping peacefully next to one another. "_Th–they're so cute...!_" she thought, her emerald green eyes gleaming as she stared at them. Even though the twins were pale and had powder blue hair, the resemblance they had to Rin was incredibly strong, leaving absolutely no doubt he was their father.

The blonde noticed that one of the twins (the boy) was finally coming out of his slumber. He whimpered, a sad pout set on his small features.

"Ah— don't cry, Nobu-kun! You don't want to wake Shinju-chan up, do you?" Shiemi mumbled in a very low voice, and the baby boy simply stared at her innocently with wide, electric blue eyes that were exactly like Rin's. Before he could cry, she picked the baby boy up and held him in her arms— and she felt a glowing warm inside herself when she noticed he was giggling at her. Shiemi laughed warmly, "you really are a nice boy, aren't you?"

It actually surprised her— the fact the half demon kids were this calm and friendly.

They were exactly in the same situation as their father: their demonic heritage didn't match their good hearted nature. Shiemi recalled that when she learned about Rin's lineage, people's thrust on him faltered; after all, he wasn't the son of any demon— he was the son of _Satan_, the king of _all_ demons. Rin, however, ended up proving her (and Suguro, and Konekomaru, and the others that judged him _because_ of his lineage) that they were wrong at thinking he was, or could be evil. Rin was actually a kind hearted person; he just had been cursed with a demon heart.

Still holding the baby in her arms, Shiemi looked up at the clock, and realized that Yukio was late. He had told her he would come to pick the twins up at 12:30 pm, but it already was 13:50 pm, and the fact he was so strict when it came to schedules (something she was aware of as he was always scolding his older brother for being late at missions) made her feel slightly worried. "Yuki-chan..."

And then, almost ironically considering her thoughts, someone knocked the door of the shop. "Shiemi-san?"

"Come in, Yuki-chan! It's open!" Shiemi told him, and then Yukio walked inside the shop— and along with him his nephew and his niece.

Shiemi observed the two little kids very carefully— the two kids had blue hair (even though while the boy's was navy blue, the girl's was denim blue) and like his twin siblings, they both shared a pretty strong resemblance to Rin— especially the boy, who practically looked like a small version of him excepting for his eyes, which were colored an icy blue.

"Hello there, Yoru-kun, Chi-chan!" Shiemi waved at the children, a sweet, cozy smile across her lips.

Despite their tremendous physical likeness, the Okumura siblings were completely different personality wise. Chiasa (the girl, who was one year younger than his brother) blushed and mumbled a quiet, "h–hello" before hiding behind Yukio's back, while Yoru (the eldest brother out of all the siblings) simply gave the blonde a toothy grin, and replied with a cheerful, "'sup!" as he waved back at her.

想

"Yukio-ojisan! Yukio-ojisan!" Yukio looked up from the tests he was correcting to his little niece, who was agitated as though she had seen a ghost. "You _have_ to see this!" He opened his mouth to ask her what was going on, but even before he could speak a word, Chiasa grabbed him by the sleeve of his coat and started leading him. "You won't believe it... Yoru-nii is a _magician_!"

Yukio frowned. "A magician...?" he asked, arching his eyebrow at the girl's words.

"Yup! He can—" Chiasa suddenly cut herself off, placing her tiny hands over her giggling mouth of hers. "Yoru-nii told me not to tell you... But he'll show you! Quick, let's go!"

A bad feeling filled the pit of his stomach; probably because of the endless worst case scenarios that were invading his thoughts. Yukio knew they were just innocent children, but the fact they were pure hearted didn't make them any less dangerous. Because of the demonic blood running through their veins, most people automatically considered them as treacherous creatures— and maybe, what the little kids thought as _wondrous magic_, others saw as _terrifying witchcraft_.

Opening the door of the room she shared with his little brother, Chiasa beamed, "Yoru-nii! I brought Yukio-ojisan!" Almost as though he didn't notice their presences, the little magician remained silent— he was sitting on the floor, an annoyed frown across his face as he stared at the palm of his hands— which were deeply burnt. "Yoru-nii...?"

Snapping out of his trance, Yoru jumped in startle. "Chiasa?! Wh... what are you doing here?!" he shouted, standing up from where he was sitting and hidding his wounded hands behind his back. He noticed his uncle was there too, and assuming his little sister had told on him, he bared his fangs (just like a rabid beast) and threw a piercing glare at her. "Chiasa you traitor! I told you it was a _secret_!" Yoru barked, hands balled up into fists. "I _hate_ you, stupid!" And then he simply ran away, leaving a confused Yukio and a devasted Chiasa behind.

魔

Ever since that day, Yoru had been distant from his little sister— nay, from everyone around him.

Yukio didn't know what to do at a situation like this. No matter how much he tried to talk with the little boy, he would refuse to speak— almost as though he was hiding something rather dark behind that silence; and Chiasa wouldn't say anything either, simply because she adored her older brother with all her heart and feared he would hate her (even more than he already did) if she were to reveal his so precious secret. Yukio wasn't clueless, though; even if the children didn't speak, he had a thesis of what was going on (which actually was one of his _worst_ fears), but he had to see it with his own eyes to confirm it— and he didn't know he would _today_.

Yukio received an unexpected phone call; screaming, loud bangs, and a young woman pleading him to come and control— "_this demon child! He's destroying everything...!_" And those words were enough reason for him to rush towards the kindergarten. He arrived nearly after ten minutes, only to see one of the worst scenarios imaginable: neighboors, passers-by, teachers and children were all standing outside; watching as the entire day care center burnt in blue flames. Amongst the crowd, Yukio spotted his little niece, whose electric blue eyes were glued on the kindergarten being devoured by the demonic blue fire.

"Chiasa!" he yelled, and the alluded girl turned around to look at him. Yukio kneeled in front of her and grabbed her by her fragile shoulders. "Chiasa... Where is your brother?"

"Inside," Chiasa replied, her answer sending chills through her uncle's spine. "But don't worry, Yukio-ojisan. Yoru-nii is okay... because those flames are magical and they don't burn." Yukio simply stared at her, his turquoise eyes wide in both shock and confusion. "I already told you; Yoru-nii is a magician... He... can make blue flames with his mind. It was fun, and I thought they were pretty because they were blue! But... but sometimes he couldn't control them... and he ended up burning himself. That wasn't fun at all... I really wanted to tell you, but he told me it was a secret and... I'm... I'm sorry...!"

As Chiasa burst in tears, Yukio stood up from where he was kneeling and rushed towards the burning building— hoping for the best, but at the same time, prepared for the worst.

判

The disastrous kindergarten incident soon became widely known around the world. To ordinarly people who had no knowledge about demonology, the event became a hot topic around Japan because of the gravity of the catastrophic situation. To the vatican and the exorcist community, on the other hand, it quickly became a world wide controversial matter because of the_ blue color_ of the flames that had burnt down the building._  
_

Naturally, the vatican took action as soon as they learned who had been the root of such a chaotic commotion— and that was why Yukio was at the opera courthouse. At that moment he was standing on the witness stand, a composed expression across his face despite the hundreds pair of judging eyes were staring at him— and the forest green orbs of a certain flamboyant demon were amongst them.

"I'd like the court to look at the following images," the judge said, as he turned around a monitor showing several pictures of the incident— pictures that were already shown countless times in the media. "Okumura-sensei, this incident... You were present when it took place, am I correct?" Yukio gave an affirmative nod. "Then would you be kind enough to tell the court _who_ or _what_ caused it?"

Yukio remained silent, bitting his lower lip at the memory that flashed in his head. His turquoise eyes wandered over the crowd as he tried to think a way out of this complicated situation, but he suddenly missed his trail of thought when he noticed that Mephisto is up there, looking down at him while wearing a wide, mischievous smirk across his lips.

The silence inside the courthouse became heavy, and the judge started to get impatient. "Okumura-kun... Shall I remind you that you swore to tell the truth, the whole truth, and nothing but the truth?"

There was a pause, and Yukio took a deep breath before speaking up, "Two weeks ago... Okumura Yoru— the eldest of Okumura Rin's children, showed a side of his demon heart. His body... It erupted in blue flames." Immediately, the whole courtroom broke into gasps and murmurs. "However," he said, elevating his tone of voice. "He didn't hurt anyone. The flames... They certainly _did_ burn down the building, but they weren't harmful to humans. They felt warm to the touch— which leads me to think he had them under control."

His defense words, despite logical and considerable, didn't seem to convince the grigori. "That doesn't mean he's not a potential threat to humanity. That child is not an ordinary demon; he's strong enough to use the blue flames despite being such a young age— and the rumpus he caused with them is proof enough he's too dangerous to be left alive, and so are his siblings, who most likely inherited the blue flames too."

The lack of trust from the vatican wasn't surprising; Rin was always going to be considered a threat for humanity— and so were his children, who were cursed with the same demonic lineage as him.

"I agree. We can't risk letting another _blue night_ happen," said another examinator. "Still, this is an unexpected problem... We considered Okumura Rin as an unique case— we didn't foresee he could pass on the flames to his offsprings. Further, he was to _seal up_ their demonic nature just in case something like this could happen, and if he did as was agreed, the seal shouldn't have broken so easily."

Yukio frowned in confusion. "_What...? Nii-san was supposed to seal them?_" he thought, but was smart enough to remain silent.

"May I have a word, please?" Everyone in the courtroom turned to look in the direction of the voice, and saw it was no one other than Mephisto— also known as _Johann Faust V_, the peculiar principal of the prestigious True Cross Academy, and also as _Samael_, the demon king of space and time.

"Go ahead, Sir Pheles." The purple haired demon's lips curved into a big, malevolent smirk.

"... There's no denying that these children— nay, any spawn with satanic lineage is a dangerous threat to humanity. However, I _do_ believe killing them is not a wise option... especially considering they could make weapons of incredible power if we start raising and training them as such," suggested Mephisto, his words captivating everyone's attention in the court.

Yukio threw a vexed glare at the purple haired demon, but the latter simply ignored him and continued with his convincing speech.

"Okumura Rin, the father of these demon children... He awakened the blue flames at the late age of fifteen. We didn't have the chance to raise him as the weapon he was meant to be, nor could we exploit the potential he had to its fullest. But his children... They're a completely different case," Mephisto explained, arms open as he spoke passionately. "The demon Okumura-sensei talked us about is nothing but a small child— yet despite his young age, he already caused an incident of this magnitude. Can you even begin to imagine what he will grow into when he reaches his father's age...? Wouldn't it be a wise choice to make him and his siblings our allies— nay, our_ weapons_, instead of our enemies?"

Yukio remained quiet as murmurs rose throughout the entire opera courtroom— although despite his composed attitude, panic was filling his mind as he knew the court _was_ considering the demon's proposal of turning Rin's children into mindless weapons of destruction. "_I'm sorry, Nii-san... I... can't do anything..._" Teeth gritted in frustration, he mentally apologized to his older brother, even if he knew that not even a thousand apologies would be enough to fix the promise he had broken— the promise of that _everything would be okay_.

"It's as Sir Pheles says— these children are as blessed as potentially dangerous, but I believe the key is what we choose to do with them," there was a pause, until the judge asked the final question. "Everyone... Shall we take a majority vote?"

獄

Yoru despised rainy days.

He thought that maybe the sun was shy and that was why it hid behind the storm clouds, and assumed that if he stopped looking at the sky through the window, it eventually would come out. So he turned around and waited patiently, staring at his baby siblings instead, who were sleeping peacefully in their crib.

Everything was silent, and Yoru truly enjoyed it— but such soothing atmosphere was soon interrupted when a bunch of people dressed in black coats (apparently exorcists, just like his father and his uncle) broke into his home. All they told him was to stay quiet, and they looked so tall and intimidating that the usually rebellious boy simply remained silent and obeyed their orders.

The next thing he knew was that he and his three siblings were being dragged to a frightening, labyrinthic place full of cages. Being the curious child he was, he let his icy blue eyes wander around the cryptic place, and he noticed there were people like him imprisoned in there (people who had tails, sharp teeth and pointed ears), and he couldn't help but feel as though he was visiting some sort of twisted, esoteric zoo— and soon after he became part of it as he was locked in a cold, obscure cell. Fighting the urge to cry, he sat in a corner and hugged his legs, hoping everything was only a nightmare.

"Dear me, such discourteous people they are..." Yoru lifted his gaze but fond no one that could have spoken to him— that is, until he spotted a small cricket next to him. The small insect was rather peculiar; it was white and pink, and it had a little hat on its head that went along perfectly with the tiny ribbon around its neck. Being the curious child he was, he stretched out his arm and tried to grab the bug, but even before his fingers could even grasp it, a thick, pinkish smoke suddenly spread all over the cell, clouding his vision.

When the smoke finally cleared, he saw the little bug was gone— and instead there was a tall, slender purple haired man standing in front of him. "I would appreciate it if you didn't touch my clothes, thank you very much~" he sang, and Yoru simply stared at him, intimidated by the demon's height. "Oh, how rude of me! I didn't even introduce myself..." And with that said, he knelt in front of Yoru and offered him a handshake, which the boy hesitantly took. "My name is Mephisto Pheles," he smirked, a demonic gleam in his forest green eyes, "A pleasure to meet you, Okumura Yoru-kun..."

Then, Mephisto stood up, eyeing the little demon skeptically.

"I'm..." Yoru trailed off, his icy gaze downcast. "I'm going to die, right...? They're... going to kill me."

Mephisto blinked in surprise, because honestly, he didn't expect such a tetric (yet _accurate_) statement from a young child. "Well... Not if _I_ can avoid it," he snickered, his words catching the demon child's attention. "You see, humans are very complex creatures. They have a rabid desire of knowledge— but at the same time, they are ironically scared of the unknown. Humans judge, despise and finally annihilate the unknown in fear that the world balanca they're so used might change into something new for them, and _you_," he paused, and pointed his index finger at him. "_You_ are a threat for that balance— as you were born with a power that could change the world."

"A power that could change the world...?" Yoru asked, puzzled. "You... you mean the flames?"

"Oh, indeed I do," Mephisto replied. "Those flames of yours are a blessing, even if humans consider them a curse."

Yoru glowered, clenching his small fists as hard as he could. "I... I didn't _choose_ this! I—"

"Indeed, you didn't choose this cruel fate... but there is still a decision you can make," Mephisto said, and the little boy tilted his head in curiosity. With a cheerful "eins, zwei, drei~!" and a snap of fingers, the purple haired demon made a black piece of paper pop out of nowhere. It flew through the air, until Yoru caught it on his hands and frowned at realizing the weird symbols written on it. "_That_ is your passage to a whole new world... Drop a single drop of your blood onto it and— well, it'd be pretty boring if I told you, wouldn't it...? Better discover it yourself~!" There was a pause, until he turned around and added: "You can either die as a slave, or rule as a king, Okumura Yoru-kun... The decision is yours~!" And then, even before Yoru could react and answer, the demon dissapeared in a poof smoke— just like a _real magician_.

Yoru didn't dwell much on it; he bit his thumb until the metallic taste filled his mouth, and the instant he let a drop of his blood fall onto the paper, the hieroglyphics written on it started to glow a red color. Startled by such surreal occurrence, he dropped the piece of paper— which, as soon as it touched the ground, got replaced by growing gate to another dimension.

Bodiless demon heads murmured "_come home, prince_" or "_jump in, young master_" as Yoru stared through the ornated gateway, having a war inside his head. He didn't want to die, and the idea of ruling as a king sounded rather appealing— but at the same time, he didn't want to be evil, nor did he want to leave his precious family— however, despite his decision, the gehenna gate had already caught him, and now he had no escapatory. Yoru screamed his lungs out, but his horrified cries fell on deaf ears, and it didn't take long until the gate had swallowed him whole.

* * *

**a/n:  
**wOW +5000 words _wtf_. weeell idk this is a fanfic about how rin's children destroy the world i hOPE_ YOU LIKE IT_.  
speaking seriosuly im a sucker for future au / children au stories so i thought id give this a try? i hope you guys like it and um im sorry if it sucks, its just i havent written for a long time and my writing is kinda shit right now and oH btw. before anyone asks about my other blue exorcist story... tbh im not sure what to do with it. i feel my writing style has changed a lot plus i think the story s_UCKS rEALLY bA_D? idk. im planning to rewrite it tho (_not_ publish a rewrite, just fix grammar mistakes and awkward writing) and im probably not going to update it till i do that. pLEASE DONT H_ATE M_E OK I_ L_OVE YO_U GUYS I TRULY DO. ok bye_


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